Control for fluid motors



Patented May .17, 1938 UNITED STATES PATENT OFFICE Application July 1 1,

7 Claims.

This invention relates to improvements in fluid motor actuated intermittently operated machines,

such as ironing presses, forming, molding, casting machines and the like, and more particularly to. control means for controlling the operation of the fluid motor of such machines.

Machines of the type referred to have a closing and an opening movement during which one member, as a pressing jaw, die, or mold, is moved respectively towards and away from a companion member. a

The object of the present invention is to pro vide a simple and efiicient control means for fluid motors employed for the actuation of intermitl5 tently operated machines, in which two manually operated valve means in combination with the fluid motor preferably control all operations of the machine and serve a multiplicity of purposes, namely:

(1) The safeguarding of the hands of the operator by requiring the use of both hands of the operator to actuate the manuals of the two spaced apart valve means to effect closing of the machine from wide open position to nearly closed position, or to a position under light pressure when one of the relatively movable coacting machine members is resiliently mounted or is provided with a padding,

(2) The further safeguarding of the hands of the operator by preventing the proper operation of the machine if one of the valve means should become stuck or its manual be tied in operated position,

' (3) The effecting of final closed position and locking of the machine in that position, after the machine has reached nearly closed position or a position under light pressure, by the release of the manuals of the valve means by the operator, so that the operator may attend to other duties while the machine remains closed, and

(4) The unlocking of the machine, permitting it toopen preferably by the momentary actuation of the manual of one of the valve means.

Other objects and advantages of the invention will be pointed out and will become apparent as the description proceeds.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing the invention, reference is had to the accompanying drawing in which my invention is shown as applied to a press and in which like characters designate corresponding parts in all the views.

Figure 1 is a side view of a fluid motor actuated 1936, Serial No. 90,193

press with part of the frame of the press and the fluid motor shown in section, the manually operated control means and their conduit connections being shown more or less diagrammatically and removed from the press to more clearly illustrate the invention. In this view the press is in wide open position and the control means are in normal or inoperated position.

Figure 2 is a view similar to Fig. 1, the press however being shown in nearly closed position with the control means in operated position.

The press illustrated in the drawing has a frame or base I0 having a bracket or arm II. Coacting members, such as dies, jaws, molds, or the like, are provided to have relative movement toward and away from each other to close and open the press respectively. As here shown, a member or upper die I2 is fixed to the bracket II of the frame [0 and coacts with a movably mounted companion member or lower die I 3. Guide rods I4 fixed in the upper member I2 and slidable in the lower member l3 are provided to hold the members in alignment.

A fluid actuator or motor generally designated I5 and including a cylinder I6 and a piston or plunger l1 movable in the cylinder is the means for moving the lower member l3 toward the upper member l2 to close the press. A piston rod I8 connected to the piston or plunger I! in the cylinder 16 extends to the outside of the cylinder and is connected to the lower member I3 by means of a right hand and left hand threaded turnbuckle or nut 19, the threads coacting with corresponding threads on the lower member I3 and on the piston rod l8. Rotation of the turnbuckle or nut I9 will adjust or move the lower member l3 relative to the piston rod I8 in the axial direction of the piston rod for a purpose to be described later.

The cylinder I6 is supported or mounted on the frame ID by means of a flange 2U integral with the cylinder and fastened by cap screws 2| extending through the flange 20 and threading into the frame Ill. The screws 2| at the same time also serve to fasten a cylinder cover or head 22 to the cylinder IE to close one end thereof. The other end of the cylinder is here shown as closed by an end wall integral with the peripheral wall 23 of the cylinder. The cover 22 is provided with a central opening through which the piston rod I8 extends and is also provided with a stufiing box 24 around the piston rod to prevent leakage of actuating fluid along the piston rod.

The actuating fluid may be any compressible ton or plunger type. These valve means are fas-.

tened to the frame of the machine in spaced apart relation to each other, far-enough to require the use of both hands of the, operator to manipulate the manuals of the valve means at the same time.

As here shown, each valve means has a housing 21. The housing constitutes the walls of a bore or chamber of cylindrical form, and a number of portholes or openings, at least three, as here shown, extend from the bore or inside chamber to the outside of the housing through the walls thereof in directions transverse to the axis of the cylindrical bore.

. A valve piston or plunger having two disc portions 28 and 29 and a portion or stem 30 between the disc portions, or spacing the disc portions apart, is slidably mounted in the bore of thehousing-with the peripheries of the disc portions in fluid-tight contact with the cylindrical wall of the bore. The disc portions 28, 29 are each sufflciently thick to completely close off a porthole or opening and the spacing between the disc portions, or the length of the stem 30,.is such that fluid may. flow between two portholes through the space between the disc portions or around the stem 36, While one of the disc portions closes off the remaining or third porthole or opening.

A manual or push button 3| is connected to one end of the valve piston or plunger and extends to the outside of the housing. Pressure on the manual or push button by the operator will cause movement of the valve plunger in one direction into operated position. A spring or springs 32 press against the other end of the valve plunger for yieldingly opposing movement or actuation thereof by means of the manual and for returning the 'valve plunger to normal or inoperated position when the manual is released by the operator. A cap'33 in one end of the valve housing 21 serves as abutment for the other end of the valve returning spring and also coacts with the valve plunger to prevent it from moving beyond operated posi tion when actuated by the operator. A shoulder 34 around the manual or push button 3| coacts with the valve plunger to prevent it from moving beyondnormal or inoperated position under the influence of spring 32. Clearance between manual 3| and shoulder 34 of the valve housing and a hole 35 in cap 33 prevents the valve plunger from becoming air bound.

The portholes or openings in the valve housings 21 of valve means 25 and 26 are connected to a conduit system, establishing communication of the valvemeans. with a source of fluid supply, with the cylinder of fluid motor l5, with atmosphere, and interconnecting the valve means themselves. Thus, from the drawing, it will be apparent that one porthole in the housing of both valve means 25, 26 connects with a fluid supply line 36, a sec-' ond porthole in the housing of valve means 25 connects said valve means with one end of the cylinder iii of fluid motor l by means of a conduit 31, whereas the corresponding porthole in the housing of valve means 26 is connected by means of a conduit 38 to a porthole or opening 39 in the peripheral Wall 23 of the cylinder ['6 at a point between the ends of the cylinder or spaced apart from the conduit 31 in the direction toward the other end of the cylinder. The third port hole in the housing of valve means 25 is connected to a conduit 40, which communicates with the conduit 33, and the third portholein the housing of valve means 26 opens into atmosphere as cation between conduits 40 and 38 may be established indirectly by, for instance, connecting the conduit '40 to'a porthole or opening in the housing of valve means 26 at a point in the radial plane of the porthole connected to conduit 38.

In a modified form of construction, as shownin Fig.2, the conduit 38 consists of two branches, one, as described above, connecting the valve means'26 withthe cylinder It at a point spaced apart fromthe conduit connection 31 to the cylinder 16 in the direction toward the other end of the cylinder, and anotherbranch 42Jconnecting-the valve means 26 with the said other end of thecylinder. This branch 42 is provided with a check valve 43' permitting flow of motive fluid through the branch from the cylinder only. An additional check valve 44 may be provided in the branch 38, permitting flow through this branch toward the cylinder only. The purpose of this modified form of construction will be apparent from the description of the operation, though it may be stated here, that in all forms of construction shown and described, a compressible and expansible motive fluid may be used, Whereas in the modified form of construction, shown in Fig. 2, a non-compressible motive fluid, or liquid, may be employed also.

The valve means 25 when in normal or inoperated position, as shown in Fig. 1, disconnects conduit 3! from the fluid supply line 36 and connects it to conduit 40, and when inoperated position, as shown in Fig. 2, connects conduit 3-! to the fluid supply line 36 and disconnects it from conduit 46. r I

The valve means 26 when in normal or inoperated position, as shown in Fig. 1, connects conduits 38 and 42 to the fluid supply line 36 and disconnects them from exhaust M or atmosphere, and when in operated position, as shown in Fig. 2, disconnects conduits 38 and 42 from the fluid supply line 36 and connects them to the exhaust 4| or atmosphere.

Thus, when both valve means 25 and 2 6 are in normal or inoperated position, as shown'in Fig. l, motive fluid flows from the fluid supply line 36 through valve means 26, conduit 38, and porthole 35, to cylinder l6 and also through conduit 40, valve means 25 and conduit 31 to one end of the cylinder l6.

From this it is apparent that, when the valve means 25, 26 are in normal or inoperated position and the piston H in the cylinder I6 of the fluid motor is in normal or inoperated position with the press being wide open, motive fluid will enter the cylinder on both sides of the piston in the cylinder. Thus, while the motive fluid entering the cylinder through conduit 31 behind or at the rear of the piston ll tends to move the piston to close the press, the motive fluid entering the cylinder through conduit 38-and porthole 39 ahead or at the front of the piston opposes actuation of the piston to close the press.

, Since the cylinder area at the front of the piston however is reduced by the cross-sectional areaof the piston rod l8, the motive fluid pressure on the opposite sides. of the piston is not exactly balanced and the piston would move to close the press, wereit not for the fact that in the press construction shown in the drawing, the combined weight of piston |1, piston rod |8, turnbuckle I9 and lower member |3 not only compensates for this loss of pressure area but also tends to return thepiston to normal or inoperated position whenever motive fluid is free to enter the cylinder on both sides of the piston. In case this combined weight is not sufficiently great or, due to different construction of the press does not perform these functions, a spring or springs 45 may be provided to assist in opposing actuation of the piston to close the press and to return the piston to normal or inoperated position to open the press.

In view of the foregoing, it should be borne in mind that the fluid motor I is single-acting only, in that motive fluid under pressure entering the cylinder behind the piston will actuate the piston to close the press if the motive fluid ahead of the piston is exhausted or reduced in pressure, andin that return of the piston to normal or inoperated position to open the press is achieved by the combined weight of the actuated parts or by separate returning means whenever the pressure on both sides of the piston is substantially the same.

In operation, first to be described in connection with a construction not using the optional conduits 42 and check valves 43 and 44 and no exhaust being provided in the cover 22 of cylinder 23, actuation of both valve means 25 and 26, moving their plungers into operated position, as shown in Fig. 2, will cause motive fluid, as compressed air, to flow from the supply line 36 through valve means 25 and conduit 31 to the cylinder l6 behind the piston l1, while at the same time, motive fluid flows from the cylinder ahead of the piston through porthole 39, conduit 38, valve means 26, and exhaust 4| to atmosphere. The piston |1 will now move to close the press until it reaches the position shown in Fig. 2 sufflciently past and uncovering the porthole 39 to permit the fluid entering the cylinder through conduit 31 to exhaust from the cylinder through porthole 39 and conduit 38, through valve 26 to exhaust 4|, whereby the piston will be held in this position. Preferably, by means of the turnbuckle 9, the lower press member 13 is so adjusted relative to piston rod l8 and piston |1 that it comes close to or in light contact with the press member l2 when the piston reaches this position, so that the operator is prevented from getting his fingers between the press members when he subsequently releases the manuals of the valve means 25, 26.

Upon release of valve means 26 and 25 successively in the order named, or simultaneously, by the operator, the valve plungers reassume the position shown in Fig. l, and motive fluid will again flow to the cylinder through conduits 31 and 38. Since however, at this time, the piston is in a position past the porthole 39, the fluid from both conduits 31 and 38 enters the cylinder behind the piston and as the cylinder space behind the piston only is now connected to the fluid supply line, the piston will move into the position shown in dotted lines in Fig. 1, moving the press into final closed position or into a position under high pressure. Also, due to the open fluid connections with the fluid supply line 36, the piston is held or locked in this position by the fluid pressure in the supply line.

It is to be understood, of course, that the adjustment 01' the piston relative to the lower member I3 by means of the turnbuckle l9 may be such, that the press reaches closed position when the piston reaches the position shown in Fig. 2 wholly or partially past the porthole 39 or even while the piston still covers the porthole. If in the latter case care is taken that no fluid from the porthole can get past the portion of the piston separating the porthole from the cylinder space in front of the piston, upon release of the valve means the fluid will continue to enter the cylinder behind the piston through conduit 31 only and hold or look the piston in operated position.

To release the press from closed position and return the piston to normal or inoperated position, it is merely necessary to momentarily actuate the plunger of valve means 28 into operated position, whereupon air will flow from the cylinder through porthole 39, conduit 38, valve means 26 to exhaust 4|, and also through conduit 31, valve means 25, conduit 40 to valve means 26 and exhaust 4|. As soon as the piston has passed the porthole 39 on its return stroke, the operator may release the valve means 23, the motive fluid then again entering the cylinder on both sides of the piston through conduits 31 and 38. The piston will continue on its return stroke under the influence of the combined weight of the actuated parts or spring 45, the air in the cylinder behind the piston being pushed through conduit 31, valve means 25, conduits 40 and 38 to the other side of the piston, performing the function of a shock absorber to slow down the last portion of the return stroke of the piston and of the opening movement of the press. By holding the valve means 26 in operated position somewhat longer, a quicker opening of the press may be obtained.

When using a compressible motive fluid, such as air or steam, in the above described construction, operation of both valve means to effect closing of the press will cause the fluid, due to its expanding nature, to quickly exhaust from the cylinder in front of the piston through porthole 39 and conduit 38 and, by the time the piston covers the porthole, air of atmospheric pressure will be trapped in front of the piston. If further movement of the piston is required to close the press, this air will be more or less compressed depending on the size of the space in the cylinder left in front of the piston after the piston covers the porthole 39, said space being large enough to permit only a relatively slight compression of the trapped air by the partly penetration of the piston into said space, as compared to the pressure of the motive fluid.

In order to partly overcome this possible disadvantage, means, as the branch 42, have been provided to continue exhausting the cylinder in front of the piston during the time the piston moves past and covers the porthole 39, thereby reducing the amount of penetration by the piston into the trapped air, resulting in less compression of said air. When the piston has uncovered the porthole, the motive fluid escaping therethrough from behind the piston will not be able to flow through the conduit 42 due to the check valve 43 blocking its passage to the cylinder in front of the piston.

Furthermore, due to the fact that in this modified form of construction the fluid infront of the piston continues to exhaust after the pistonhas cut off, or covers, the porthole 39, a non-compressible, or liquid, motive fluid may be employed, provided, the relative adjustment of the piston and the press member I3 is such, as to allow flnal closing of the press while the piston still covers the porthole 39. In this case, the operator must hold the valves 25, 26 in operated position until. the press reaches said final closed position, whereupon release of the valve means 25, 26 to normal, or inoperated, position serves to hold, or lock, the press closed.

If the relative adjustment of the piston and the press member I3 is such that still considerable movement of the piston is necessary to close the press after the piston has passed the porthole, entailing considerable compression of the trapped air, the constructionmay be further modified by the provision of the additional check valve 44 in conduit 38 permitting flow of fluid through said conduit in the direction to the cylinder only. In this case the fluid may be a compressible gas or a non-compressible liquid. The fluid in the cylinder in front of the piston will be exhausted through conduit 42 alone until the press reaches final closed position, while conduit 38 serves to admit fluid to the cylinder in front of the piston after it has passed the porthole 39 on its return stroke.

Release of the press from closed, or locked, position to open position is obtained in practically the same manner as described above in connection with the first form of construction by moving valve means 26 into operated position, the only exception being that the fluid behind the piston cannot escape partially through porthole 39 and partially through conduit 31, but has to exhaust entirely through conduit 31, valve means 25, which is at this time in normal, or inoperated, position, through conduit 40, conduit 38, valve means 26, which is at this time in operated position, to exhaust 4|. As soon as the piston has passed the porthole 39 on the return stroke, valve means 26 may be returned, or released, to normal position, whereupon motive fluid may enter the cylinder on both sides of the piston and the press returned to open position as described above.

The accomplishment of the object of the invention with regard to safeguarding the hands of the operator by requiring the use of both hands of the operator to actuate the manuals of the two spaced apart valve means will be apparent from the following:

(1) Actuation of valve means 25 alone merely changes the indirect connection of conduit 31 to the fluid supply line 36 through valve means 25, conduit 40, and valve means 26 to a direct connection to the fluid supply line 36 through valve means 25 without effecting operation of the machine.

(2) Actuation of valve means 26 alone will exhaust the motive fluid from the cylinder IS on both sides of the piston through conduit 38 and valve means 26 from one side and through conduit 31, valve means 25, conduit 46, and valve means 26 from the other side.

- (3) Release of the valve means 25 after the press has been set in operation by actuating both valve means will exhaust the cylinder on both sides of the piston, as described in the previous paragraph and the press will return to open position.

,(4) Release of the Valve means 26 after the press has been set in operation by the actuation of both valve means and before the piston passes the-porthole 39 on its outward stroke, will admit air through the cylinder on both sides of the piston, and thepress will return to open position.

(5) Release of both valve means after .the press has been set in operation and before the piston has passed the porthole 39 on its outward stroke, will admit air to the cylinder on both sides 'of the piston and the press will return to open position.

means .25 will prevent proper operation of the machine by not permitting the piston to. return to normal or inoperated position since the cylinder behind the piston cannot then be exhausted through conduit 31.

('7) Tying down or becoming stuck of valv means 26 will prevent final closing of the ma-. chine and will also prevent locking of the machine in operated position.

In Fig. 1, I have shown a manually operable exhaust valve 50 connected by means of a conduit 5| to a porthole 52 in the peripheral wall of the cylinder I6 at a point between the end of the cylinder to which conduit 31 is connected and porthole 39.

When the press is locked closed with the piston I! in the position shown in dotted lines in Fig. .1,

the fluid behind the piston may be exhausted through porthole 52, conduit 5| and exhaust valve 50, provided, the fluid is permitted to escape faster than it is supplied by conduits 31 and 38. To open the press by means of exhaust valve 50 it is merely necessary to return the piston 11 to a position past the porthole 39 in the direction of the return stroke, whereupon motive fluid will enter the cylinder IS on both sides of the piston, after which the piston will continue its return stroke under the influence of the combined weight of the actuated parts of the machine'or of spring 45 as described before.

This exhaust valve 50 may be grouped with valve means 25 on the frame of the machine, so that the operator may open the press with one hand by operating valve means 26 and with the other hand by operating exhaust valve 50. Also, the exhaust valve 50 may be located at a point remote from the machine to permit'the foreman and also the operator, who may tend to other duties while the press is locked closed, to open the press from a distance.

What I claim is:

1. The combination of a fluid motor including a cylinder and a piston movable in the cylinder; a supply line for a compressible and expansible motive fluid; a pair of spaced apart valve means connected to the fluid supply line; a first conduit connection between one of said pair of valve means and one end of the cylinder; a second conduit connection between the other of said pair of valve means and the cylinder and connected to the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder; and a third conduit connected to the first valve means and communicating with the second conduit; said first valve means being normally in a position to close the first conduit to the fluid supply line and open it to the third conduit and operable to open the first conduit to the fluid supply line and close it to the third conduit; and said second valve means being normally in a position to open the second and third conduits to the fluid supply line-and (6) Tying down or becoming stuck of valve operable to close them to the fluid supply line and open them toatmosphere.

2. The combination of a fluid motor including a cylinder and a piston movable in the cylinder and normally in a position near one end of the Qcylinder and operable to move away from said one end toward the other end of the cylinder; means for returning the piston to normal position; a supply line for a compressible and expansible motive fluid; a pair of spaced apart valve means connected to the fluid supply line; a first conduit connection between one of said pair of valve means and one end of the cylinder; a second conduit connection between the other of said pair of valve means and the cylinder and connected to the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder; and a third conduit connected to the first valve means and communicating with the second conduit; said first valve means being normally in a position to close the first conduit to the fluid supply line and open it to the third conduit and operable to open the first conduit to the fluid supply line and close it to the third conduit; and said second valve means being normally in a position to open the second and third conduits to the fluid supply line and operable to close them to the fluid supply line and open them to atmosphere.

3. The combination of a fluid motor including a cylinder and a piston movable in the cylinder and normally in a position near one end of the cylinder; a supply line for a compressible and expansible motive fluid; a pair of spaced apart valve means connected to the fluid supply line; a first conduit connection between one of said pair of valve means and said one endof the cylinder to permit the flow of fluid to and from the cylinder behind the piston; a second conduit connection between the other of said pair of valve means and the cylinder and connected to the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder to permit the flow of fluid to and from the cylinder in front of the piston; a third conduit connected to the first valve means and communicating with the second conduit; said first valve means being normally in a position to close the first conduit to the fluid supply line and open it to the third conduit and operable to open the first conduit to the fluid supply line and close it to the third conduit; and said second valve means being normally in a position to open the second and third conduits to the fluid supply line and operable to close them to the fluid supply line and open them to atmosphere.

4. The combination of a fluid motor including a cylinder and a piston movable in the cylinder and normally in a position near one end of the cylinder; a motive fluid supply line; a pair of spaced apart valve means connected to the fluid supply line; a first conduit connection between one of said pair of valve means and said one end of the cylinder to permit the flow of fluid to and from the cylinder behind the piston; a second conduit connection between the other of said pair of valve means and the cylinder and connected to the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder to permit the flow of fluid to and from the cylinder in front of the piston; a third conduit connected to the first valve means and communicating with the second conduit; and additional means connected to the other end of the cylinder to permit exhaust of the cylinder in front of the piston; said first valve means being normallyin a position to close the first conduit to the fluid supply line and open it to the third conduit and operable to open the first conduit to the fluid supply line and close it to the third conduit; and said second valve means being normally in a position to open the second and third conduits to the fluid supply line and operable to close them to the fluid supply line and open them to atmosphere.

5. The combination of a fluid motor including cylinder and a piston movable in the cylinder; a motive fluid supply line; a pair of spaced apart valve means connected to the fluid supply line; a first conduit connection between one of said pair of valve means and one end of the cylinder; a second conduit connection having two branches connected to the other of said pair of valve means, one branch communicating with the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder, and the other branch communicating with the cylinder near said other end thereof and having a check valve therein permitting fiow of fluid through the branch in the direction away from the cylinder only; anda third conduit connected to the first valve means and communicating with the second conduit; said first valve means being normally in a position to close the first conduit to the fluid supply line and open it to the third conduit and operable to open the first conduit to the fluid supply line and close it to the third conduit; and said second valve means being normally in a position to open the second and third conduits to the fluid supply line and operable to close them to the fluid supply line and open them to atmosphere.

6. The combination of a fluid motor including a cylinder and a piston movable in the cylinder; a motive fluid supply line; a pair of spaced apart valve means connected to the fluid supply line; a first conduit connection between one of said pair of valve means and one end of the cylinder; a second conduit connection having two branches connected to the other of said pair of valve means, one branch communicating with the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder, and the other branch communicating with the cylinder near said other end thereof, each branch having a check valve therein permitting flow of fluid through each branch in one direction only; and a third conduit connected to the first valve means and'comrnunicating with the second conduit; said first valve means being normally in a position to close the first conduit to the fluid supply line and open it to the third conduit and operable to open the first conduit to the fluid supply line and close it to the third conduit; and said second valve means being normally in a position to open the second and third conduits to the fluid supply line and operable to close them to the fluid supply line and open them to atmosphere.

7. The combination of a fluid motor including a cylinder and a piston movable in the cylinder; a motive fluid supply line; a pair of spaced apart valve means connect-ed to the fluid supply line; a first conduit connection between one of said pair of valve means and one end of the cylinder; a second conduit connection between the other of said pair of valve means and the cylinder and connected to the cylinder at a point spaced apart from the first conduit connection in a direction toward the other end of the cylinder; a third conand third conduits to the fluid supply line and operable to close them to the fluid supply line and open them to atmosphere; and a manually operable normally closed exhaust valve connected to the cylinder at a point between said one end 1 of the cylinder and the point at which the second conduit communicates with the cylinder.

GERal-LARD H. J. IBAULE; 

